package com.zx._03_并发.chapter_02_synchronized;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.StopWatch;

/**
 * 线程安全——原子性——使用synchronized修饰代方法，实现线程安全的计数器
 */
@Slf4j
public class Demo_02 {

    // 请求总数
    public static int clientTotal = 5000;

    // 同时并发执行的线程数
    public static int threadTotal = 200;

    public static int count = 0;

    public static void main(String[] args) throws Exception {
        StopWatch sw = new StopWatch();
        ExecutorService executorService = Executors.newCachedThreadPool();
        final Semaphore semaphore = new Semaphore(threadTotal);
        final CountDownLatch countDownLatch = new CountDownLatch(clientTotal);
        sw.start("");
        for (int i = 0; i < clientTotal; i++) {
            executorService.execute(() -> {
                try {
                    semaphore.acquire();
                    add();
                    semaphore.release();
                } catch (Exception e) {
                    log.error("exception", e);
                }
                countDownLatch.countDown();
            });
        }
        countDownLatch.await();
        executorService.shutdown();
        sw.stop();
        log.info("count:【{}】,{}", count, sw.prettyPrint());
    }

    private synchronized static void add() {
        count++;
    }
}
